Heartwood activation on mainnet
This release supports the Heartwood activation on mainnet, which will occur at a block height of 903000 (mid-July), following the targeted EOS halt of our 2.1.2-3 release. Please upgrade to this release, or any subsequent release, in order to follow the Heartwood network upgrade on mainnet.
The Heartwood network upgrade deploys ZIP 213, which allows miners to mine directly into shielded addresses. It also deploys ZIP 221, enabling Flyclient support by changing the semantics of existing block header fields. The deployment process for the Heartwood upgrade is described in ZIP 250.
In order to help the ecosystem prepare for the mainnet activation, Heartwood has already been activated on the Zcash testnet. Any node version 2.1.2 or higher, including this release, supports Heartwood on testnet as well.
Mining to Sapling shielded addresses
After the mainnet activation of Heartwood, miners will be able to mine directly into a Sapling shielded address. Miners should wait until after Heartwood activation before they make changes to their configuration to leverage this new feature.
After activation of Heartwood, miners can add mineraddress=SAPLING_ADDRESS to their zcash.conf file, where SAPLING_ADDRESS represents a Sapling address that can be generated locally with the z_getnewaddress RPC command. Restart your node, and block templates produced by the getblocktemplate RPC command will now have coinbase transactions that mine directly into this shielded address.
